The Who and What of Greenhouse Problems! Objective 11.00 11.01: Explain potential problems related to bedding plant production 11.02: Hypothesize causes of problems with bedding plants 11.03: Propose possible solutions to problems with greenhouse plant production

Potential Problems (Click to view) Cultural Disorders Germination Problems Fertilization Problems Uneven growth Tall and spindly growth Diseases Seedlings falling over Lower leaves brown, rotting, and drying Insects Plants missing Holes in leaves or plant parts missing

Cultural Disorders A cultural disorder is anything that can cause a plant a problem but is not caused by a type of pest (disease, weed, or insect)

Cultural-Germination Problems Causes Improper temperatures Over-watering or underwatering Chemical residues in medium Seed planting depth Low quality seeds

Cultural-Germination Problems Correction or Prevention Use high-quality seeds Plant at proper depth Use medium with no chemical residues Maintain proper temperatures Maintain proper moisture levels

Cultural-Fertilization Problems Causes Lack of nutrients Root injury Improper pH of medium Excessive fertilization Manganese Deficiency

Cultural-Fertilization Problems Correction or Prevention Test soil or media Apply correct amounts and kinds of nutrients Use pH correcting materials

Cultural-Uneven Growth Causes Poor mixing of medium Uneven moisture levels Unlevel flats Poor grading of seedlings

Cultural-Uneven Growth Correction or Prevention Proper mixing of media Even watering Grading seedlings by size and quality Placing flats level

Cultural-Tall and Spindly Growth Causes Too much nitrogen fertilizer Overwatering Low light intensity (too much shade) High temperatures

Cultural-Tall and Spindly Growth Correction or Prevention Use the correct amount of nitrogen Reduce frequency of watering Lower temperature Provide more light Use growth retardant such as B-Nine SP

Cultural-Slime or Algae Causes Too much watering

Cultural-Slime or Algae Correction or Prevention Water less often Clean out fertilizer tanks Don’t leave any standing water

Diseases Help me! I’m dying.

Disease An abnormal condition of an organism that impairs plant functions

Disease Disease is a plant disorder caused by an infectious pathogen or agent

Three Conditions Necessary for Diseases Host plant Disease causing organism or pathogen must be present Favorable environment for disease organism to develop

Groups of pathogens Bacteria Fungi Viruses Parasitic plants- mistletoe, dodder, lichens (attach to plants)

Plant Disease Must be identified before they can be treated Warm temperatures and moist conditions in greenhouse plant production make most horticulture plant diseases worse

Disease Preventing plant disease through sanitation and insect control is much easier than treating the disease.

Diseases Blight Canker sores Damping off Galls Leaf spot Mildew Mosaic Rots Rust Smut Wilt

Diseases-Seedlings Falling Over Causes Stem rot Damping-off

Diseases-Seedlings Falling Over Correction or Prevention Use sterilized media Apply fungicides Improve air circulation around plants

Diseases-Brown, rotting leaves Causes Botrytis a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes

Diseases-Brown, rotting leaves Correction or Prevention Increase air temperature Increase air circulation around plants Use proper fungicide

Damping off Fungal disease Causes young plants and seedling to rot off at soil level

Mildew Grows on leaf surfaces Upper and lower leaves Appears as white, gray or purple spots Example is powdery mildew

Mosaic Caused by a virus Leaves have irregular mottled areas with patterns Ranges from dark green to light green to yellow to white

Rots Causes plants to decay and die Usually has a unique smell

Rust Causes small spots on leaves Resembles yellow, orange, brown or red rust Mainly on underneath of leaf

Insects An arthropod with three pairs of legs and three body regions; insects may have one or two pairs of wings

Insects-Plants Missing Causes Slugs Snails Cockroaches

Insects-Plants Missing Correction or Prevention Use baits and pesticides

Insects-Holes in Leaves Causes Aphids Mealy Bugs Scale Insects Thrips Whiteflies Flea beetles Fungus Gnats Leaf miners Cutworms Caterpillars

Insects-Holes in Leaves Correction or Prevention Use of recommended pesticides to control insects

You’ll never look at a bug the same. Insect bad guys! You’ll never look at a bug the same.

Damage Damage depends on the type of mouthpart Chewing Sucking

Chewing- Beetles Eat leaves Stems Flowers Fruits Nuts

Beetles Correction Oil or soap

Chewing- Caterpillars Larva Moths Butterflies Fuzzy and hair Eat young leaves and stems Roll up in leaves, makes leaves curl

Caterpillars Correction Tent Caterpillars-kerosene to burn them

Sucking- Aphids Pierce and suck juices Plant lice Cause stunted growth, yellow spotted leaves Sticky substance and black mold Attracts ants

Aphids Correction Apple Cider Vinegar Oil or Soap Malathion Lady bugs

Sucking- Mealy Bugs Pierce and suck from underside of leaves Suck in leaf axils Causes yellow appearance Sticky secretions

Mealy Bug Corrections Oil or soap Neem

Sucking- Thrips Chews and then sucks Causes plant tissue to become speckled or whitened Leaf tip withers Leaf curls and dies

Thrips Correction Insecticidal Soap

Sucking- Whiteflies Feeds on underside of young leaves Little flying white specks when plants are shaken

Whiteflies Correction Marathon Lady bugs

Sucking- Mites Attack underside of leaf Causes leaves to turn gray to grayish Severe infestations cause webbing Insects can be red

Slugs & Snails Problems Plants Missing

Slugs & Snails Correction or Prevention Use baits and pesticides Beer Caffeine (Coffee)